Chemistry of Detergents and Carpet Cleaning Chemicals
The four fundamentals of soil removal:
- Chemical action
As you decrease the use of one of the four fundamentals of
soil removal, the need for using one or more of the remaining fundamentals
increases. Temperature is especially critical when removing cooking grease
and other materials with a high melting point. Agitation aids in lifting
matted fibers, distributing pre-conditioning agents, and soil suspension.
Chemical action is what the chemicals are designed to accomplish and what
follows below. Of course, the longer the chemical has time to work on
the soil, the more likely the soil will be removed. Time extension is
one of the primary purposes of the presprays.
How does a warm water extraction cleaning detergent, such
as our PCA™
Formula 5 work? There are nine basic steps that a properly
formulated detergent follows in the wet extraction carpet cleaning process:
- Electrostatic Charge Cancellation:
Have you noticed how kids like to rub balloons on their
shirts and then stick them to the wall? That is due to the electrostatic
charge on the balloon. In like manner, before all the soil can come
off; the detergent has to cancel any electrostatic charge bonding the
soil to the fibers.
Have you noticed that nearly all detergents are alkaline?
Why is that? Because nearly all soils and most staining agents are acidic.
As a result, an alkaline cleaner performs best at removing these soils
because they bring these acids into solution.
In fact, ALL OTHER THINGS BEING EQUAL, the higher the pH,
the better the cleaning. But, we are restricted to only moderate pH
levels on carpets (below pH 10 on stain-resistant nylon carpets). pH
levels above 10 have a very adverse effect on the stain-blocking mechanism
in stain-resist nylon carpets and should never be used on natural fibers.
Additionally, all other things being equal, the higher the pH, the more
likely dyes will bleed and browning will occur.
We can actually carry out a chemical reaction between the
detergent and certain oily soils in the carpet. This chemical reaction
is called SAPONIFICATION. These oils are vegetable/animal
fat and oil from cooking, body oils, etc. Oils like these will react
with alkali to form soap. An example of this is how soap was made in
the frontier days. The mother would heat up a kettle of bear grease
in a big kettle with water. The grease would just melt and float on
the water because it hates water. She then added lye or wood ash, and
the fat was turned into soap, which not only dissolves in water but
also is a detergent! This is another reason that higher pH usually results
in better cleaning.
Sequestration is a fancy chemical name meaning basically
water-softening. There are four reasons for adding a sequestering agent
to a detergent:
However, we strongly recommend the use of a water softener
in areas of extremely high water hardness to further improve cleaning
and prevent scale build-up in the clean water tank.
- Prevent clogging of the nozzle filters, etc.
- Make the detergent much more effective (water hardness reduces
the effectiveness of detergents).
- Prevent the dulling effect of scum formation, just like the scum
formation on your bathtub.
- Prevent resoiling due to scum formation.
If you look at a piece of soot through a microscope, you
will see that it is an uneven mass filled with air pockets not likely
to dissolve in water Ė in fact it even floats on water. A conventional
detergent "eats" away at this soil mass layer by layer. That’s
fine if you’re scrubbing a tile floor, but not in the carpet cleaning
business! We only have microseconds to get that dirt out!
Therefore, a properly formulated carpet wet extraction detergent
has to instantly destroy this dirt particle, which is exactly what happens.
The detergent molecule actually drives the water into the particle,
forces the air out of the soil to fully wet out all surfaces, and explodes
it apart. This action can be described as releasing CHEMICAL ENERGY.
Now the soil must be evenly dispersed (distributed evenly)
throughout the solution because it wants to come back together.
The soil is now removed, but it still really would much
prefer going back to the carpet. Therefore, a good detergent has to
contain suspending agents which keep the soil particles "suspended"
in the detergent solution until the solution is pulled out of the carpet
by the vacuum and air movement action.
Without this suspending action, it is quite possible to
end up with a carpet looking dirtier and dingier than when you started!
Why? You brought up all the "muck" from the "sewer"
but it then spread out on the surface of the carpet before you got it
all picked up! Additionally, the heavier grit particles fall back to
the backing. Without good suspension, you will frequently have streaking,
resulting in having to go back and reclean.
Emulsification is the process of removing those oils that
do not saponify; i.e., they donít react with alkali and turn into soap.
These are motor oils, exhaust fumes, common pollution oils, lubricants,
silicones, furniture polish, sun tan lotion, tobacco smoke residue,
lubricating grease, oils from skin and pet hair, etc.
We can remove these in two ways: strong solvents or emulsification.
Essentially, oil hates water (85% of the cleaning challenge).
Our objective is to get oil and water married! We put a molecule into
our detergent, which we call EMULON®. The Emulon molecule
is composed of two parts: one part of the molecule loves oil and hates
water (hydrophobic) and dissolves in oil while the other part loves
water (hydrophilic) and hates oil.
The oil-soluble end penetrates into the oil with the water-soluble
portion sticking out into the water. Hundreds of these Emulon molecules
surround this oil particle, break it into smaller particles, and pull
it into the water by changing the very nature of both the water and
A familiar example of an emulsion would be salad oil. If
you mix vinegar and oil, you get two layers. No matter how hard you
shake it or heat it, it separates into two layers! Yet, you can go to
the grocery store and find all kinds of salad dressings that donít separate!
How did they do that? They added chemical emulsifiers, which
results in a creamy emulsion that does not separate. Isn’t it
great to know that you are eating chemicals?
Now that we have done all these things to the soil, is it
ready to go up the vacuum tube yet? NO! It still has to be physically
released from the carpet by the mechanical action (mechanical energy)
of the water flow.
This would be a good place to mention thermal energy.
There has been a debate between two schools of thought as
to what is the best temperature for wet extraction cleaning.One side says
"the hotter the better", because cleaning power doubles for
every 18° increase in temperature. They say this because many chemical
reactions double for every 18° increase in temperature, above a certain
critical temperature. However, the main objective in cleaning is to be
above the melting point of the soil (try cleaning butter off a knife with
cold water vs. hot water).
The other side says that high temperatures are unsafe to carpet
and people and unnecessary. The carpet dyes and protectors are also more
readily removed at the higher temperatures.
Well, both sides are correct! ALL OTHER THINGS BEING EQUAL,
cleaning improves with increased temperature on any kind of surface. However,
there are surfactants and emulsifiers available today with which one can
formulate a product specifically to perform at its best at a particular
temperature range. By using these specialized surfactants, it is usually
unnecessary to strive for the highest temperatures possible. In fact,
cleaning compounds of this type will outperform at moderate temperatures
the old-fashioned surfactants at high temperatures! Only in the case of
extremely grease-laden carpets in restaurants is it really necessary to
increase the temperature of the Bane-Clene system.
Remember also that a loss of temperature will occur from the
solution tank to the carpet surface. Factors that determine the degree
of temperature loss are: solution hose length, distance of the tee-jet
opening from the surface of the carpet, and the outside temperature (especially
in the winter) with truck-mounted equipment outside.
Instead of using higher temperatures, use better chemicals!
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